Form tie



Patented Nov. 12, 1 935 UNTED STATES PATENT OFFICE 2,020,912 Foam 'rm Application May 31, 1934, Serial No. 728,225

4 Claims.

'I'his invention relates to an improvement in form ties for concrete construction, and has for its objectv to provide a simple form tie which will be cheap to construct, easy to use, and entirely satisfactory in service.

More particularly, the invention comprises a form tie made from a metal rod and provided with weakened points which are located within the concrete structure after the wall has been poured, the rod being then broken oii at these weakened points with the portion of the rod between the weakened points remaining Within the wall and covered by the concrete after the wall has been pointed.

The primary object of the invention is to provide means for suitably spacing the form boards and aiding in the breaking off of the form tie at the proper weakened points.

In the accompanying drawing, wherein the preferred embodiment of the invention is shown, Fig. 1 is a plan view, with parts in section, of a wall form showing one of the form ties in position; Fig. 2 is a side elevation of the structure shown in Fig. l, after the wall has been poured; Fig. 3 is a sectional view of a part .of a wall showing the broken section of the form tie remaining in the wall; and Fig. 4 is an enlarged view, in section, of a part of the form tie.

The improved formtie is adapted for use with any suitable concrete. form, which may consist of longitudinally extending boards 5, re-enforced by horizontal beams 6 and uprights 1, all of which may be used in the conventional manner. The form tie 8 consists of a section of metal rod provided with short, spaced cross-bars 9 welded to it. Located adjacent to the welded bars 9 are notches I0 which weaken the body of the rod and form break-Dif points located within the concrete structure after the wall has been poured. The rod is also provided with spaced collars II, each of which forms a fixed stop against which a washer I2 abuts, and is held by the pressure of the form boards 5. At each of its ends, the form tie is provided with an enlarged head or washer I3 against which a wedge I4 is employed to draw together the parts of the form. The pressure of A the two wedges I4 holds the form parts in position and presses the form boards 5 against the washers I2, holding the washers. firmly against the collars II. The collars Il are integrally formed on the rod 8 by distorting the body of the rod through the use of suitable dies. 'The form boards are perforated at I5 to permit the passage of the form tie, as is clearly shown in Figs. 1 and 2.

After the concrete wall structure, indicated at IB in Figs. 2 and 3, has been poured, the projecting portions of the form tie are broken oi by being engaged by a suitable tool and twisted. The breakage of the rod occurs at the weakened points Ill located within the concrete structure. 5 The bars 9 secured to the rod 8 prevent rotation or turning of the portion of the rod located within the concrete structure while the ends of the rod are being'twisted to break them off. After the ends of the rod are broken off, the openings 10 I'I in the wall are filled with concrete.

'I'he washers I2 are freely movable upon the rod 8 and while they constitute a i'lrm abutment for the form boards 5 and accurately position the form boards, they may rotate independently of 15 the form tie and consequently do not impede the twisting movement of the ends of the form tie applied to the ends of the form tie during the breaking off of these ends. The integral formation of the collars or xed stop elements II on 20 the rod 8 thickens or materially increases the strength of the rod and its resistance to fracture adjacent the outer surface of the wall structure thus preventing breakage of the rod 8 at these re-enforced points and increasing the tendency of the rod to break oii at the notches I0,' where it is desired that the breakage occur.

In use, the form tie is readily set up and as soon as the concrete is sufciently hard, the form tie is easily broken by twisting the ends of the rod 30 to cause the breakage of the rod to take place at the notches I0. The recesses I'I in the wall are then lled.

What I claim is:

l. A form tie consisting of a rod provided with 35 spaced weakened break-off points arranged to lie within the body of the concrete structure through which the form tie extends, the rod having porvtions which extend outwardly from the break-01T points beyond the faces of the concrete structure shaped to permit them to be rotatively twisted within the concrete structure to break them ofi at the break-ofi points a pair of spaced collars integrally formed on the rod and positioned to lie adjacent to the opposite faces of the concrete structure, said collars acting to increase the thickness and strength of the rod in those portions of the rod where they are located' and serving to increase the tendency of the rod to break off at the weakened points upon twisting movement of the ends of the rod.

2. A form tie consisting of a rod provided with spaced weakened break-off points arranged to lie within the body of the concrete structure through which the form tie extends, said rod b5 having end portions capable of being twisted by rotative movement in the concrete structure to break them off at the break-oi! points a pair of spaced stops integrally formed on the rod and positioned' as to lie adjacent to the opposite faces of the concrete structure, said stops acting to increase the thickness and strength of the rod in those portions of the rod where they are located and serving to' increase the tendency of the rod to break off at the weakened points upon twisting movement of the ends of the rod, and washers freely rotatable on the rodand abutting :against the stops under pressure of the form boards.

3. A. form tie consisting of a rod having weakened break-olli points, the rod being provided with end portions extending from said break-off points adaptedto be broken oiI by twisting movement about the longitudinal axis of the rod, stops on said end portions consisting of parts formed by enlargement of the diameter of the body of the rod without weakening said rod, and washers adapted to be held against said stops. the end spaced, weakened break-oi! points arranged to lie 5 within the body of the concrete structure through which the form tie extends, the rod having portionswhlch extend outwardly vfrom the breakoff points to the faces of the concrete structure shaped to permitfthem to be rotatively twisted to 10 cause them to break oi at the break-oi! points within the concrete structureand movable stop elements, each of said stop elements consisting of a collar formed by enlargement of the diameter of the body of the rod without weakening 15 the rod and a washer on the rod adapted to be pressed against the collar, those portions of the rod adapted to be broken oiI by twisting movement being movable within the washer during such twisting movement. 2o

TAMS C. SCHENK. 

